CN108947246B

CN108947246B - Foam glass ceramics compositely utilizing iron tailings and waste glass and preparation method thereof

Info

Publication number: CN108947246B
Application number: CN201810790416.6A
Authority: CN
Inventors: 杨眉; 杨博
Original assignee: China University of Geosciences
Current assignee: China University of Geosciences
Priority date: 2018-07-18
Filing date: 2018-07-18
Publication date: 2021-04-09
Anticipated expiration: 2038-07-18
Also published as: CN108947246A

Abstract

The invention provides foam glass ceramics which compositely utilize iron tailings and waste glass, which is prepared from the following raw materials in percentage by mass: 32-37% of waste glass, 26-31% of iron tailings, 20-25% of potassium feldspar, 2-5% of calcite, 0.8-1.5% of foam stabilizer, 2-4% of fluxing agent and 0-7% of foaming agent. The invention also provides a preparation method of the foam glass ceramics by compositely utilizing the iron tailings and the waste glass, which comprises the following steps: weighing waste glass, iron tailings, potassium feldspar, calcite, a foam stabilizer, a fluxing agent and a foaming agent, and mixing to obtain a mixture; grinding the mixture, adding the mixture into a mold paved with release paper, and paving and compacting; and (3) putting the mould and the mixture into a muffle furnace for firing, heating for homogenizing, heating for foaming, cooling for annealing, stopping heating, cooling along with the furnace, demoulding, polishing and drying to obtain the foam glass ceramics. The foam glass ceramics provided by the invention has the advantages of good mechanical property, light weight, heat preservation, heat insulation, flame retardance and chemical corrosion resistance.

Description

Foam glass ceramics compositely utilizing iron tailings and waste glass and preparation method thereof

Technical Field

The invention relates to the technical field of wall heat-insulating materials, in particular to foam glass ceramics which compositely utilizes iron tailings and waste glass and a preparation method thereof.

Background

The research and development and production of the wall heat-insulating material in China are late, and since the 80 s of the 20 th century, the wall heat-insulating material in China is rapidly developed, wherein the wall heat-insulating material mainly comprises: mineral wool, polystyrene foam boards, polystyrene particle heat insulation slurry, polyurethane boards and the like. The mineral wool has the advantages of good fireproof performance, low price, sound insulation effect and the like, and is widely applied to the field of continental building heat preservation in the fifth and sixty years of the last century, but the mineral wool has the defects of low tensile strength, poor durability and the like, and meanwhile, along with the mature development and application of the organic heat preservation and heat insulation material, the mineral wool gradually exits from most markets. Although the polystyrene foam board has a good heat insulation effect, the polystyrene foam board is not high in fire-release level, is easy to age, and easily releases toxic gas during combustion, so that the polystyrene foam board is not widely applied to the market.

As the fire accident of the building frequently happens, the use of heat insulation materials in the building field, especially high-rise buildings, places more and more emphasis on the fire release performance in China. The government has issued relevant policies and has greatly promoted the development of new heat-insulating materials, and the heat-insulating materials can be effectively promoted to be continuously developed along the directions of high performance, high efficiency and high environmental protection. Particularly, the development trend of domestic wall heat-insulating materials is to develop vigorously, apply the heat-insulating materials which have the comprehensive characteristics of high fire resistance, flame retardance, small deformation coefficient, simple ageing resistance, low cost and the like, meet the national energy-saving and environment-friendly requirements, and do not or less bring adverse effects to the environment in the production and use processes. Compared with the common organic synthetic heat-insulating material commonly used in the market, which has the defects of inflammability, toxic substance release during combustion, easy aging and the like, the foamed microcrystalline material serving as the inorganic heat-insulating material better meets the living requirements of people on environmental protection, health and safety and has better market prospect.

The foam glass ceramics are prepared by the processes of melting, foaming, crystallization, annealing and the like, and a powder sintering method is generally adopted. The sintering method can be divided into a two-step method and a one-step method.

The two-step method comprises the following steps: the raw materials are melted at high temperature and water-quenched to prepare the basic glass, and then the basic glass, the foaming agent, the crystal nucleus agent and the like are fired again to prepare the foam glass ceramics. The two-step method can better control the components of the raw materials, and the obtained product is more uniform, but has high requirements on equipment and high energy consumption.

The steps of the one-step method are as follows: all raw materials including the foaming agent and the crystal nucleus agent are directly mixed and sintered together to directly prepare the foam glass ceramics. Although the one-step process has simple and economic steps, raw materials are not easy to homogenize, and the matching degree of the foaming agent and the glass transition temperature of the powder is high.

Disclosure of Invention

In view of the above, the invention provides the foam glass ceramics which compositely utilizes the iron tailings and the waste glass and has good mechanical property, thermal insulation property and heat insulation property, and also provides the preparation method of the foam glass ceramics which compositely utilizes the iron tailings and the waste glass and has simple process and low energy consumption.

The invention provides a foam glass ceramics compositely utilizing iron tailings and waste glass, which is prepared from the following raw materials in percentage by mass: 32-37% of waste glass, 26-31% of iron tailings, 20-25% of potassium feldspar, 2-5% of calcite, 0.8-1.5% of foam stabilizer, 2-4% of fluxing agent and 0-7% of foaming agent.

Further, the material is prepared from the following raw materials in percentage by mass: 35.698% of waste glass 28.627% of iron tailings, 22.957% of potassium feldspar, 3.763% of calcite, 0.953% of foam stabilizer, 3.002% of fluxing agent and 5% of foaming agent.

Further, Na is selected as the foam stabilizer₃PO₄·12H₂O, the cosolvent is selected from B₂O₃The foaming agent is green alpha-SiC.

The invention also provides a preparation method of the foam microcrystalline glass, which comprises the following steps:

s1, weighing waste glass, iron tailings, potassium feldspar, calcite, a foam stabilizer, a fluxing agent and a foaming agent, and mixing to obtain a mixture;

s2, grinding the mixture, adding the ground mixture into a mold paved with release paper, and paving and compacting;

and S3, firing the mold and the mixture in a muffle furnace, heating to 830-930 ℃, carrying out heat preservation homogenization, heating to 1040-1080 ℃, carrying out heat preservation foaming for 5-30 min, cooling and annealing after foaming is finished, stopping heating, cooling to room temperature along with the furnace, demolding, polishing and drying to obtain the foam glass ceramics.

Further, in step S2, the grinding process includes: the mixture was added to a vibration sample mill and milled at 710rad/min for 3min to give a mixture having a particle size of 200 mesh or less.

Further, in step S2, the release paper is alumina release paper, and the mold is a corundum mold.

Further, in step S3, the mold and the mixture are placed into a silicon-molybdenum rod muffle furnace for firing, the temperature is raised to 880 ℃, the temperature is kept for homogenization for 30min, then the temperature is raised to 1060 ℃, the temperature is kept for foaming for 10min, the temperature is lowered to 600 ℃ after foaming is finished, annealing is performed, the temperature is lowered to 400 ℃ at the cooling rate of 100 ℃/h, then heating is stopped, the temperature is cooled to room temperature along with the furnace, and demolding, polishing and drying are performed to obtain the foam glass ceramics.

Further, in step S1, Na is selected as the foam stabilizer₃PO₄·12H₂O, the cosolvent is selected from B₂O₃The foaming agent is green alpha-SiC.

The technical scheme provided by the invention has the beneficial effects that:

1. the foam glass ceramics prepared by taking the iron tailings and the waste glass as main raw materials not only can greatly save high-quality mineral raw materials and reduce the production cost, but also provides an ideal path for the treatment of the iron tailings and the waste glass, and has remarkable economic, social and environmental benefits;

2. the foam glass ceramics prepared by the invention takes diopside as a main crystal phase, has the advantages of good mechanical property, light weight, heat preservation, heat insulation, flame retardance and chemical corrosion resistance, and has wide development and application prospects in the fields of heat preservation, heat insulation, building materials and the like;

3. the foam glass ceramics are fired by adopting a one-step powder sintering method, compared with the traditional two-step method, the method has the advantages of simple process and low energy consumption, and the homogenization process is originally adopted in the material firing process, so that the sintering of the raw materials and the homogenization of the components are promoted, and the performance of the material is improved;

4. the method and the process for preparing the foam glass ceramics by compositely utilizing the iron tailings and the waste glass have the advantages of easy operation and easy popularization.

Drawings

FIG. 1 is a process flow chart of a preparation method of foam glass ceramics by using iron tailings and waste glass compositely.

FIG. 2 is a heat treatment system of the foam glass ceramics which utilizes iron tailings and waste glass compositely.

FIG. 3 is a scanning electron microscope image of the non-corroded foam glass ceramics of example 1 under different magnifications of the invention.

Fig. 4 shows the coexistence of crystal phase and glass phase on the surface of the foam glass ceramics of example 1 after corrosion according to the invention.

Fig. 5 shows the morphology of the crystal phase on the surface of the foamed glass-ceramic of example 1 after etching.

Fig. 6 is two typical crystal morphology maps and EDS spectra of fig. 5 taken in accordance with the present invention.

Fig. 7 shows the morphology and EDS spectra of the glass phase and the crystalline phase of the same region of the foamed glass ceramic of example 1 according to the invention.

Figure 8 is an XRD pattern of the foamed glass-ceramic of the present invention at different homogenization temperatures.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings.

The embodiment of the invention provides foam glass ceramics for compositely utilizing iron tailings and waste glass, which is prepared from the following raw materials in percentage by mass: 32-37% of waste glass, 26-31% of iron tailings, 20-25% of potassium feldspar, 2-5% of calcite, 0.8-1.5% of foam stabilizer, 2-4% of fluxing agent and 0-7% of foaming agent, wherein the waste glass is waste plate glass, and the foam stabilizer is Na₃PO₄·12H₂O, cosolvent selected from B₂O₃The foaming agent is green alpha-SiC.

Referring to fig. 1 and fig. 2, an embodiment of the present invention further provides a preparation method of the above-mentioned foamed glass ceramic by using iron tailings and waste glass compositely, including the following steps:

step S1, weighing 32-37% of waste glass, 26-31% of iron tailings, 20-25% of potassium feldspar, 2-5% of calcite, 0.8-1.5% of foam stabilizer, 2-4% of fluxing agent and 0-7% of foaming agent according to mass percentage, and mixing to obtain a mixture; wherein the waste glass is waste plate glass, and the foam stabilizer is Na₃PO₄·12H₂O, cosolvent selected from B₂O₃The foaming agent is green alpha-SiC;

step S2, grinding the mixture to make the particle size less than 200 meshes, then adding the ground mixture into a mould paved with demoulding paper, and paving and compacting;

and step S3, placing the mold and the mixture into a muffle furnace for firing, quickly heating to 830-930 ℃, then carrying out heat preservation homogenization at the temperature, heating to 1040-1080 ℃, carrying out heat preservation foaming for 5-30 min, cooling and annealing after foaming is finished, then stopping heating, cooling to room temperature along with the furnace, demolding, polishing and drying to obtain the foamed microcrystalline glass.

The following describes the foam glass ceramics which utilizes iron tailings and waste glass in a composite manner and the preparation method thereof in detail with reference to the examples.

Example 1:

weighing 35.698% of waste glass, 28.627% of iron tailings, 22.957% of potassium feldspar, 3.763% of calcite and 0.953% of Na according to mass percentage₃PO₄·12H₂O，3.002％B₂O₃Mixing with 5% green alpha-SiC to obtain a mixture; adding the mixture into a vibration sample grinder, grinding for 3min at the speed of 710rad/min to ensure that the granularity of the mixture is less than 200 meshes, then weighing the ground mixture, adding the mixture into a corundum mold paved with alumina demolding paper, and paving and compacting; putting the corundum mold and the mixture into a silicon-molybdenum rod high-temperature muffle furnace, quickly heating to 880 ℃, carrying out heat preservation homogenization for 30min, then heating to 1060 ℃, carrying out heat preservation foaming for 10min, quickly cooling to 600 ℃ after foaming, starting annealing, then slowly cooling at the speed of 100 ℃/h, cooling from 600 ℃ to 400 ℃ after two hours, finishing the annealing process, then stopping heating, cooling to room temperature along with the furnace, carrying out demolding treatment, polishing into a regular shape by using a metallographic specimen polishing machine, and drying to obtain the foam microcrystalline glass.

The density of the foamed glass ceramics prepared in example 1 is 0.496g/cm³The true density is 2.722kg/m³The porosity was 81.6%, and the flexural strength was 5.07 MPa.

In order to further understand the formation of crystals in the foam glass ceramics prepared in example 1, the invention utilizes SU8010 ultra-high resolution field emission scanning electron microscope to test the crystals, figure 3 is a Scanning Electron Microscope (SEM) topography of the non-corroded foam glass ceramic of example 1 at different magnifications, figure 3a is a scanning electron microscope topography of the non-corroded foam glass ceramic of example 1 at preliminary magnification, fig. 3b is a scanning electron microscope image of the non-corroded foam glass ceramic of example 1 at a further magnification, as can be seen from fig. 3a, on the flat glass surface, many small-particle crystals are embedded uniformly, and the sample is observed in a magnified way, as can be seen from figure 3b, the surface of the crystal had a number of rods, which were presumed to be crystals prepared in example 1.

Since the crystals are not attached to the surface of the glass but embedded in the glass, the sample needs to be further processed if the morphology of the crystals is to be observed. It is considered that the glass component and the crystal component are different in the rate of corrosion by hydrofluoric acid when reacting with hydrofluoric acid. The invention soaks the foam microcrystalline glass sample prepared in the embodiment 1 into hydrofluoric acid with the mass fraction of 1 percent, processes the sample for 90 seconds, then shoots the appearance of the processed sample, FIG. 4 is the coexisting morphology of the crystal phase and the glass phase on the surface of the foamed microcrystalline glass after corrosion, FIG. 4a is the coexisting morphology of the crystal phase and the glass phase on the surface of the foamed microcrystalline glass after corrosion in initial amplification, FIG. 4b is a further enlarged view of the appearance of the foam glass ceramics after corrosion, where the glass phase is thicker on the surface of the foam glass ceramics, the coexistence of the glass phase and the crystal phase can still be seen after corrosion, and the crystal phase is buried into the glass phase, as can be seen from fig. 4a, after the corrosion, a part of the crystal phase under the glass phase is exposed on the surface of the sample, and then the magnification of the visual field is increased, and the rod-shaped crystal exposed at the hole of the sample can be clearly seen from fig. 4 b; FIG. 5 shows the crystal phase morphology of the surface of the foam glass ceramics after etching, FIG. 5a shows the crystal phase morphology of the surface of the foam glass ceramics after etching under initial magnification, FIG. 5b shows the crystal phase morphology of the surface of the foam glass ceramics after etching under further magnification, and it can be seen from FIG. 5 that the glass phase is hardly seen in the thin portion of the surface of the foam glass ceramics, such as the inside of the air hole, after etching, the appearance and the stacking manner of the crystal can be better observed, the crystal contained in the sample is rod-shaped, the length of the crystal is intensively distributed between 5 μm and 8 μm, the width and the height are similar, the crystal is intensively distributed between 1 μm and 2 μm, the crystal distribution is comparatively random, and no obvious stacking manner exists.

Two more typical crystals in fig. 5 were selected and their elemental compositions were measured by X-ray Spectroscopy, and the results are shown in fig. 6, fig. 6a is a selected typical crystal morphology diagram in fig. 5, fig. 6b is an EDS (Energy Dispersive Spectroscopy) spectrum of a selected typical crystal in fig. 5, fig. 6c is a selected another typical crystal morphology diagram in fig. 5, and fig. 6d is an EDS spectrum of a selected another typical crystal in fig. 5, and it can be seen from fig. 6 that the crystals contained the main elements of Si, O, Mg, and Ca (wherein the peak of carbon is also higher because the conductive paste was spread under the sample and the peak of carbon was treated as an alien peak during analysis), which is similar to diopside [ CaMg (SiO) (where the peak of carbon is treated as an alien peak during analysis), which is similar to diopside [ SiO (SiO)₃)₂]The compositions of (A) and (B) are matched, so that it can be judged that the rod-like crystal is a diopside crystal, and in the element composition, there are Fe and Al elements in a certain content, because Mg in the diopside crystal²⁺Can be made of Fe²⁺、Al³⁺Substitutions form a class homography.

In order to further study the elemental composition of the whole system, the present invention uses an X-ray energy spectrometer to separately test the crystalline phase and the glass phase in the same region, and the results are shown in fig. 7, fig. 7 is the morphology and EDS spectra of the glass phase and the crystalline phase in the same region, fig. 7a is the morphology and EDS spectra of the glass phase in the same region, fig. 7b is the EDS spectra of the glass phase in the same region, fig. 7c is the morphology and EDS spectra of the crystalline phase in the same region, and fig. 7d is the EDS spectra of the crystalline phase in the same region, and it can be seen from the elemental content in fig. 7 that the content of Mg element contained in the glass phase is less than that in the crystalline phase, because diopside crystallization causes the Mg element to be enriched in the crystalline phase. The glass phase and the crystal phase both contain an alkali metal element Na, while an alkali metal element K is only in the glass phase because the atomic radius of the K element is larger and is difficult to enter the crystal structure, and the atomic radius of the Na element is smaller and can be in the pores in the crystal.

In conclusion, the experimental sample of the foam microcrystalline glass prepared in the embodiment 1 of the invention has good crystallinity, the crystals are uniformly distributed in the glass, the length of the crystals is concentrated between 5 and 8 μm, the width and the height of the crystals are similar, and the concentration of the crystals is between 1 and 2 μm. The observed crystalline phase is dominated by the diopside crystalline phase. The glass phase has similar components with the crystal phase, the content of Mg element in the glass phase is less than that in the crystal phase, and the content of K element is more than that in the crystal phase.

In order to determine the influence of the foaming temperature, the using amount of the foaming agent, the homogenizing temperature and the foaming time on the performance of the prepared foamed microcrystalline glass, on the basis of the embodiment 1, different foaming temperatures, using amounts of the foaming agent, homogenizing temperatures and foaming times are respectively set for carrying out experiments, and the flexural strength and the density of the foamed microcrystalline glass prepared under different conditions are measured, wherein the specific experimental processes are shown in the embodiment 2 to the embodiment 5.

Example 2:

example 2 differs from example 1 only in that: the foaming temperatures were set to 1040 ℃, 1050 ℃, 1070 ℃ and 1080 ℃, respectively, and the rest was substantially the same as in example 1.

The flexural properties (flexural strength) and density data of the foamed glass-ceramics obtained at different foaming temperatures are shown in table 1:

TABLE 1 flexural Strength and Density data of foamed glass ceramics obtained at different foaming temperatures

Example 3:

example 3 differs from example 1 only in that: the amounts of addition of the blowing agent green α -SiC were set to 0%, 1%, 3%, 4%, and 7%, respectively, and the rest was substantially the same as in example 1.

The flexural properties (flexural strength) and density data of the foamed glass-ceramics obtained with different amounts of blowing agent are shown in table 2:

TABLE 2 flexural Strength and Density data for foamed glass ceramics produced with different amounts of foaming agent

Example 4:

example 4 differs from example 1 only in that: the homogenization temperatures were set to 830 ℃, 860 ℃, 900 ℃ and 930 ℃, respectively, and the rest was substantially the same as in example 1.

The flexural properties (flexural strength) and density data of the foamed glass-ceramics obtained at different homogenization temperatures are shown in table 3:

TABLE 3 flexural Strength and Density data of the foamed glass-ceramics obtained at different homogenization temperatures

The crystal compositions of the foamed glass ceramics prepared at different homogenization temperatures are shown in table 4, fig. 8 is an XRD (X-ray diffraction) spectrum of the foamed glass ceramics at different homogenization temperatures, and as can be seen from table 4 and fig. 8, the most kinds of crystals are precipitated at 880 ℃. The kind of precipitated crystals is reduced regardless of whether the homogenization temperature is increased or decreased. When the main crystal phase does not change and other secondary crystal phases are separated out, the strength of the product can be improved. The main crystal phase diopside, the secondary crystal phase wollastonite, the kaolinite and the quartz which are precipitated at 880 ℃ have different behaviors when being stressed in the same direction, thereby better dispersing external force and achieving higher strength. It can be seen from fig. 8 that the prepared foam glass ceramics contain more crystalline phases.

TABLE 4 Crystal composition in foamed glass-ceramics obtained at different homogenization temperatures

Example 5:

example 5 differs from example 1 only in that: the foaming time was set to 5min, 15min, 20min and 30min, respectively, and the rest was substantially the same as in example 1.

The flexural properties (flexural strength) and density data of the foamed glass-ceramics obtained at different foaming times are shown in table 5:

TABLE 5 flexural Strength and Density data of foamed glass ceramics obtained at different homogenization temperatures

From examples 1 to 5, considering the flexural strength and density data of the foamed glass ceramics comprehensively, the invention shows that when the addition amount of the green alpha-SiC of the foaming agent is 5%, the thermal treatment system is homogenizing for 30 minutes at 880 ℃ and the foamed glass ceramics prepared under the condition of foaming for 10 minutes at 1060 ℃ has the best performance.

The foam glass ceramics prepared by taking the iron tailings and the waste glass as main raw materials not only can greatly save high-quality mineral raw materials and reduce the production cost, but also provides an ideal path for the treatment of the iron tailings and the waste glass, and has remarkable economic, social and environmental benefits; the foam glass ceramics prepared by the invention takes diopside as a main crystal phase, has the advantages of good mechanical property, light weight, heat preservation, heat insulation, flame retardance and chemical corrosion resistance, and has wide development and application prospects in the fields of heat preservation, heat insulation, building materials and the like; the foam glass ceramics are fired by adopting a one-step powder sintering method, compared with the traditional two-step method, the method has the advantages of simple process and low energy consumption, and the homogenization process is originally adopted in the material firing process, so that the sintering of the raw materials and the homogenization of the components are promoted, and the performance of the material is improved; the method and the process for preparing the foam glass ceramics by compositely utilizing the iron tailings and the waste glass have the advantages of easy operation and easy popularization.

The features of the embodiments and embodiments described herein above may be combined with each other without conflict.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The foam glass ceramics compositely utilizing the iron tailings and the waste glass are characterized by being prepared from the following raw materials in percentage by mass: 32-37% of waste glass, 26-31% of iron tailings, 20-25% of potassium feldspar, 2-5% of calcite, 0.8-1.5% of foam stabilizer, 2-4% of fluxing agent and 3-7% of foaming agent, wherein Na is selected as the foam stabilizer₃PO₄·12H₂O, the cosolvent is selected from B₂O₃The foaming agent is green alpha-SiC;

the preparation method of the foam glass ceramics by compositely utilizing the iron tailings and the waste glass comprises the following steps:

s3, placing the mold and the mixture into a muffle furnace for firing, firstly heating to 830-930 ℃, carrying out heat preservation homogenization, then heating to 1040-1080 ℃, carrying out heat preservation foaming for 5-30 min, cooling and annealing after foaming, then stopping heating, cooling to room temperature along with the furnace, demolding, polishing and drying to obtain the foam glass ceramics,

in step S2, the grinding process includes: the mixture was added to a vibration sample mill and milled at 710rad/min for 3min to give a mixture having a particle size of 200 mesh or less.

2. The foam glass-ceramic according to claim 1, which is prepared from the following raw materials in percentage by mass: 35.698% waste glass, 28.627% iron tailings, 22.957% potassium feldspar, 3.763% calcite, 0.953% foam stabilizer, 3.002% fluxing agent and 5% foaming agent.

3. The foamed glass-ceramic according to claim 1, wherein in step S2, the release paper is an alumina release paper, and the mold is a corundum mold.

4. The foamed glass-ceramic according to claim 1, wherein in step S3, the mold and the mixture are placed in a silicon-molybdenum rod muffle furnace for firing, the temperature is first raised to 880 ℃, the temperature is kept for homogenization for 30min, then raised to 1060 ℃, kept for foaming for 10min, and after foaming is finished, the temperature is first lowered to 600 ℃ for annealing, then the temperature is lowered to 400 ℃ at a cooling rate of 100 ℃/h, then the heating is stopped, the furnace is cooled to room temperature, and the foamed glass-ceramic is obtained after demolding, polishing and drying.